DTUS0413

Dental Tribune U.S. Edition | April 2013A16 INduStry NEWS Implant position in esthetic zone Since the advent of modern root form osseointegrated implant dentistry in 1952, clinicians have strived for improve- ments in implant position- ing in the esthetic zone to achieve predictable restor- ative and esthetic results. Years of clinical experience in congruence with controlled clinical studies have helped establish param- eters as a guide for these results. Estab- lishing a treatment plan and clinical protocol prior to implant placement is paramount. Treatment planning traditionally be- gins with comprehensive medical and dental evaluations, articulated diagnos- tic casts, radiographs, cone-beam com- puted tomography (CBCT) scans and a diagnostic wax-up. Patient demands must be taken into consideration prior to surgery, and presurgical mockups may be necessary to convey the infor- mation to the patient. The advancement of CBCT technol- ogy has led dentistry into a new realm of dimensional accuracy. In combina- tion with the use of a surgical or guided stent, proper 3-D positioning of an im- plant has led to more accurate clinical results. The importance of the implant position can be manifested in the four dimensionally sensitive positioning criteria: mesiodistal, labiolingual and apico-coronal location, as well as im- plant angulation.1 The ultimate goal is not only to avoid sensitive structures, but to respect the established biological principles to achieve esthetic results. Mesiodistal criteria Correct implant position in a mesiodis- tal orientation allows the clinician to avoid damaging adjacent critical struc- tures. A minimum distance of 1.5 mm between implant and existing dentition prevents damage to the adjacent teeth and provides proper osseointegration and gingival contours2–4 (Fig. 1a). Dis- tances of less than 3 mm between two adjacent implants leads to increased bone loss and can reduce the height of the inter-implant bone crest. A distance of more than 3 mm between two adja- cent implants preserves the bone, giving a better chance of proper interproximal papillary height (Fig. 1b). Labiolingual criteria An implant placed too far labially can cause bone dehiscence and gingival re- cession, while an implant placed too far lingually can cause prosthetic difficul- ties. A thickness of 1.8 mm of labial bone is critical in maintaining an implant soft tissue profile5 (Fig. 2). Labially oriented implants compromise the subgingival emergence profile development, creat- ing long crowns and misalignment of the collar with respect to adjacent teeth.6 Apico-coronal criteria Peri-implant crestal bone stability plays a critical role in the presence of interden- tal papilla.7 Implants placed too shallow may reveal the metal collar of the im- plant through the gingiva. Countersink- ing implants below the level of the crest- al bone may give prosthetic advantages, but can lead to crestal bone loss. The ideal solution would be the placement of an implant equicrestal or subcrestal to the ridge. However, the existing microgap at the implant abutment junction leads to bone resorption due to peri-implant inflammation.8 It is suggested that an implant collar be located 2 mm apical to the CEJ of an adjacent tooth if no gingival recession is present9 (Fig. 3). Implant angulation Implant angulation is particularly im- portant in treatment planning for screw- retained restorations. Implants angled too far labially compromise the place- ment of the restorative screw while im- plants angled too far lingually can result in unhygienic and unesthetic prosthetic design. For every millimeter of lingual inclination, the implant should be placed an additional millimeter apically to create an optimal emergence profile.10 In general, implant angulation should mimic angulation of adjacent teeth (Fig. 4). Furthermore, maxillary anterior re- gions require a subtle palatal angulation to increase labial soft tissue bulk.11 Inclusive tooth replacement The Inclusive® Tooth Replacement Solu- tion was developed by Glidewell Labo- ratories as a complete, prosthetically driven method of restoring missing den- tition. The solution comprises treatment planning, implant placement, patient- specific temporization and the definitive restoration (Figs. 5a–5f). When utilizing the comprehensive range of Inclusive Digital Treatment Planning services, the clinician has absolute and precise con- trol of each step. The clinician has con- trol of the four dimensions of implant placement in the esthetic zone, creating a consistently predictable result. To read the full article, you can access it on the website www.inclusivemagazine.com. (Source: Glidewell Laboratories) Fig. 1a Fig. 1b Fig. 2 Fig. 3 Fig. 4 Fig. 5a Fig. 5b Fig. 5c Fig. 5d Fig. 5e Fig. 5f CDA BOOTH NO. 1348 ÿ References 1. Al-Sabbagh M. Implants in the esthetic zone. Dent Clin N Am. 2006 Jul;50(3):391–407. 2. Tarnow DP, Cho SC, Wallace SS. The effect of inter-implant distance on the height of inter-implant bone crest. J Periodontol. 2000 Apr;71(4):546–49. 3. Spray JR, Black CG, Morris HF, Ochi S. The influence of bone thickness on facial marginal bone response: stage 1 placement through stage 2 uncovering. Ann Periodontol. 2000 Dec;5(1):119–28. 4. Saadoun AP, LeGall M, Touati B. Selection and ideal tridimensional implant position for soft tissue aesthetics. Pract Periodontics Aesthet Dent. 1999 Nov–Dec; 11(9):1063–72. 5. Hermann JS, Buser D, Schenk RK, Schoolfield JD, Cochran DL. Biological width around one- and two-piece titanium implants. Clin Oral Implants Res. 2001 Dec; 12(6):559–71. 6. Kazor CE, Al-Shammari K, Sarment DP, Misch CE, Wang HL. Implant plastic surgery: a review and rationale. J Oral Implantol. 2004;30(4):240–54. 7. Berglundh T, Lindhe J. Dimension of the periimplant mucosa. Biological width revisited. J Clin Periodontol. 1996 Oct;23(10):971–73. 8. Broggini N, McManus LM, Hermann JS, Medina RK, Buser D, Cochran DL. Peri-implant inflammation defined by the implant-abutment interface. J Dent Res. 2006 May;85(5):473–78. 9. Saadoun AP, LeGall M, Touati B. Selection and ideal tridimensional implant position for soft tissue aesthetics. Pract Periodontics Aesthet Dent. 1999 Nov-Dec;11(9):1063–72. 10. Potashnick SR. Soft tissue modeling for the esthetic single-tooth implant restoration. J Esthet Dent. 1998;10(3):121–31. 11. Tishler M. Dental implants in the esthetic zone. Considerations for form and function. N Y State Dent J. 2004 Mar;70(3):22–6. Fig. 1a: Minimum distance of 1.5 mm between implant and existing dentition. Photos/ Provided by Glidewell Laboratories Fig. 1b: Minimum distance of 3 mm between two adjacent implants. Fig. 2: Proper labiolingual placement with 1.8 mm thickness of labial bone. Fig. 3: Lateral view of implant placed with collar at the level of crestal bone with adjacent teeth CEJ 2 mm coronal to the collar of the implant. Fig. 4: Proper implant angulation with screw access in the cingulum area. Fig. 5a: Inclusive Tapered Implant at placement. Fig. 5b: Inclusive custom healing abutment in place. Fig. 5c: Contoured soft tissue sulcus after healing. Fig. 5d: Screw-retained IPS e.max® crown (Ivoclar Vivadent; Amherst, N.Y.) in place. Fig. 5e: PA to verify seating of crown. Fig. 5f: Buccal view of final restoration at delivery.